Our column of May 25 included a question from a New Boston reader who wrote on April 1, in part: "I was picking up brush in my yard Saturday afternoon and saw my first butterfly. It flitted from here to there for about five minutes. Isn't that an early appearance?"

As one who makes no record of returning dates of butterflies, even though I certainly do enjoy watching these colorful, interesting creatures, I was delighted to receive a letter from Ms. Karen Hilson, past editor of "Butterfly Gardener," a quarterly magazine published by the North American Butterfly Association. Ms. Hilson wrote: "I think I may have an answer for your New Boston reader who wondered why a butterfly was seen flying on April 1, which is rather early in the year for butterfly sightings. Some butterflies species seek protection from harsh winter weather in brush and woodpiles. Your reader may have inadvertently disturbed the butterfly while picking up brush around the yard. I always do 'spring cleanup' later in the season, because not only adult butterflies, but caterpillars and chrysalids may be hidden in leaf litter.

"When my husband and I moved from Tucson six years ago, I often missed the birds and other denizens in my Sonoran Desert Garden. Your column inspired me to get to know my new animal 'neighbors.' I created a wildlife habitat with native plants that attract many birds and butterflies, so I feel at home here in New Hampshire. Thank you!

"If you have any other questions about butterflies, I would be happy to answer them."

I thank Ms. Hilson for her excellent letter, and I have recorded her name and address in my permanent record.

The insect order "Lepidoptera" is a word that means "scally-winged" and includes both moths and butterflies.

How can one tell the difference between the two that have so many contrasts as well as similarities?

Moths are as brightly colored as any butterfly, while some butterflies are as dull colored as any moth can be. Many moths travel only at night while others, like butterflies, enjoy the sunshine.

Many moths fold their wings when resting as butterflies do. Most of them can be told apart by looking at their antennae, sometimes called "feelers." The antennae of butterflies usually are slender with a knob on top, so also are some moths.

However, most moths lack the knob and appear to be feathered out. Some moths exhibit a thread-like appearance as do butterflies. I look forward to contacting Ms. Hilson, an expert in the insect order of Lepidoptera, for her comments.

According to C.C. Williams, a well-known British entomologist, there are more than 250 insects that migrate. And,the most famous of them all is the monarch butterfly.

Its autumnal, drifting movements southward are watched for with great enthusiasm by butterfly buffs. These "ultra- lights" of the insect world spend weeks traveling 2,000 miles or more to reach their chosen winter quarters.

The monarch butterfly (Danaus plexippus) is probably the best known of our native butterflies. Its pointed, pale green eggs are laid close to one of the ribs on the underside of a milkweed leaf. The caterpillar that hatches is hardly an eighth-of-an-inch long and is ravenous for only one food — the juicy tissues of the milkweed plant. Occasionally the larvae will be found on dogbane, but this is extremely rare.

Here at the farm in recent years quite a few patches of milkweed plants have been left undisturbed so that the monarchs, sometimes called the "milkweed" butterfly, would have an excellent opportunity to reproduce.

"The Audubon Nature Encyclopedia," describes their migratory travels along the East Coast of the U.S. as follows: "Monarchs drift down the Long Island shore — sometimes a thousand individuals an hour fluttering past the dunes.

They cluster on Spanish oaks at Cape May, New Jersey, when the autumn birds are going through. They also move south along the ridges of Hawk Mountain in Pennsylvania at a time of the migration of the broadwings and sharpshins.

But the full magnitude of this annual insect migration cannot be fully appreciated until a person crosses North America from Cape Cod to California in the fall of the year. Those weeks of travel reveal in nationwide cross section the southward-bound hordes of butterflies.

"On four-inch wings these migrants journey from the Canadian border to the Gulf of Mexico, and often farther, all the while traversing country they have never seen before.

"Because one monarch looks like another monarch, people see them in the mass. ... Spectacular as the massed southern movement of the butterflies may be, it is the thin, scattered return journey that presents the most puzzles."